86 Problems of Economic Biology in East Africa 



The palm patches are mostly cultivated, are owned by natives, and 

 alternate with areas of bush, forest or grass. The oldest natives in the 

 district state that their ancestors tried to grow cocoanuts on these places 

 but invariably failed. It is usually only these palmless areas which can 

 be acquired, and in a number of instances it has been found that the 

 cocoanut will not thrive in such. 



On the other liand it has frequently happened with plantations of 

 a permanent crop such as cocoanuts, coffee and citrus, that the first 

 European holder of the land, in order to save time and expense, and to 

 ensure a " quick return," has hastily ploughed and planted with immature 

 seed or weak plants. These grow for a time according to circumstances, 

 and to the new-comer, who is looking for a plantation already laid out, 

 they appear in good condition. The original holder sells his plantation 

 at a handsome profit on his outlay and is heard of no more. It is usually 

 later when the crop should be bearing that serious trouble commences, 

 and such cases are some of the most difficult with which the economic 

 biologist is confronted. 



The third point which is important in any consideration of the bud-rot 

 disease is the state of cultivation in which the plantation is kept. On a 

 certain plantation in which bud-rot had been recorded since 1912, those 

 palms in the camp for native labour were not only of greater size and of 

 more healthy appearance than those in the plantation, but in addition 

 bore fruit earlier (5-6 years) and never showed a sign of the disease. It 

 was only among the palms outside of the encampment that the disease 

 appeared. These had been planted at the same season, and the only 

 obvious difference between them was in their subsequent treatment. 

 The camp had Iteen kept scrupulously clean, no growth between the 

 huts, and therefore between the palms, was allowed, and rubbish which 

 might collect from food was never left lying about. On the other hand, 

 but a few yards away from the camp, the ground was only weeded 

 occasionally, as the supply of labour allowed, and then only between the 

 palms and not underneath them. The idea seemed to prevail that hoeing 

 up grass and weeds from the spaces between the palms and putting this 

 to rot on top of the weeds growing at the foot of each tree, would produce 

 excellent tilth. In reality, this procedure gave rise to the formation of 

 the most favourable breeding-ground for all manner of fungi and insects 

 - — not to mention the non-aeration of the root system. 



Among insect enemies, mention must be made of the rhinoceros 

 beetle {Orycles tnonoceros Ohv.). This large beetle, nearly 2 inches long, 

 flies mostly at night and feeds on the tender tissues of the youngest 



